Brush-holder for dynamo-electric machines and the like.



No. 821,197. PATENTED MAY 22, 1906.

. G. W. SPBIRS 8: J. FRITH. BRUSH HOLDER FOR DYNAMO ELECTRIC MACHINES AND THE LIKE.

APPLIUATION FILED AUG, 29, 1905.

2 SHEETS-SHEET 1.

No. 821,197. PATBNTED MAY 22, 1906.

G. W; SPBIRS 6: J. PRITH. BRUSH HOLDER FOR DYNAMO ELECTRIC MACHINES AND THE LIKE.

2 sums-sum 2.

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CHARLES WILLIAM SPEIRS, OF LONDON, AND JULIUS FRITH, OF MANCHESTER, ENGLAND. I

BRUSH-HOLDER FOR DYNAMO-ELECTRIC MACHINES AND THE LIKE.

Specification of Letters Patent.

Patented May 22, 1906.

' Application filed August 29, 1905. Serial No. 276.185.

To all whom, it ntay concern:

Be it known that we, OI-IAELEs WILLIAM SPEIRS, residing at Battersea Works, Battersea, London, and JULIUS FRITH, residing at Salford Iron Works, Manchester, county of Lancaster, England, subjects of the King of Great Britain, have invented new and useful Improvements in Brush-Holders for DynamO-Electric Machines and the Like, of Which the following is a specification.

Our invention relates to brush-holders for dynamo-electric machines and the like, and is more particularly applicable to holders for brushes consisting of carbon blocks used with commutators running at a high peripheral speed, the object of our invention being to maintain such a carbon brush in constant contact with the commutator.

'According to our invention the carbon brush is arranged in a cylinder or box forming partof the holder and communicating with an air-supply under pressure which acts directly upon the brush, or the brush can be attached to a piston which slides in the holder.

To enable our invention to be fully understood, we will describe the same by reference to the accompanying drawings, in which Figure 1 is a sectional elevation of a brushholder constructed according to our invention; and Fig. 2 is a view of a duplex brush' holder, one holder being shown in elevation and the other in sectional elevation. Fig. 3 is a sectional side elevation of the holder. Fig. 4 is a'section on the line 4 4, Fig. 2.

In the arrangement of-the invention shown in Fig. 1, a indicates a box or holder, and b the brush, which fits into the said box with an easy fit, so that it can slide therein. 0 is a hollow spindle upon which. the box a is mounted and through which a supply of air under pressure may be admitted to the closed end cl of the box above the brush, so that the tendency of the air-pressure will be to force the brush out of the box and into contact with the commutator, which in the drawing is'indicated by the letter 6, the air-pressure serving to keep the brush in constant contact with the said commutator. f is a guide which is arranged above the commutator and which serves to support the brush in its proper position against the pull due to its contact with the commutator, and g is a screw which maybe used for locking the holder in any desired position.

In the arrangement of our invention shown in Figs. 2, 3, and 4 the brush b instead of being arranged in the holder (1, so that it can be acted upon directly by the air-pressure, is arranged to fit loosely in a guide f above the commutator 'e and is acted upon by a piston h in the box a through the medium of a rod 1', which may bear directly upon the brush 6. In connection with the guide-box f we advantageously provide a lateral cylinder j, connected with a supply of air under pressure, the said lateral cylinder containing a piston 7c, which may be of the same material as the brush itself or of any other suitable material and which by being pressed constantly against the brush 7) will hold the latter well up against the side of the guide f and thus prevent chattering of the said brush. In the drawings the piston is is represented as being acted upon by a spring which will retain the piston in contact with the brush notwithstanding the failure of the air-pressure. In order to provide against the brush 1) moving out of contact with the commutator in case of the accidental failure of the airpressure, we advantageously arrange, in connection with the piston or rod, mechanism for maintaining a pressure upon the brush- A suitable arrangement of mechanism is shown and comprises a tube is, inserted into the end of the box a and having formed in it holes or slots Z Z, on the lateral faces of which rackteeth m m are cut. Upon the rod 1' and moving between these rack-teeth is a cross-bar n, carrying pawls 0, which engage with the rackteeth m. Between the cross-bar n and the foot p of the rod 71, which bears upon the brush 6, is inserted a helical spring g. The foot 1), which bears upon the brush, is not rigidly connected to the piston-rod i, but is connected therewith by a sliding connection, so as to allow of a slight movement of the brush independently of the rod 2'.

Under the action of the compressed air the piston 71/ on the rod '5 is moved outwardly in the box a and carries forward the cross-bar n the pawls 0 0 on which engage with the rackteeth m, and so prevent the movement, while at the same time the spring g. is more or less compressed. If now the air-pressure should ther forward, the spring-pawls 0 0 engaging in other teeth of the rack, so that the helical spring will always be kept under compression by the air-pressure.

Although in the foregoing description we have described the brush-holder as being mounted upon a hollow supporting-spindle through which the compressed air is passed, it will be understood that each cylinder or box a may be connected with the supply of air under pressure independently in any suit able manner.

Having now particularly described and ascertained the nature of our said invention and in what manner the same is to be performed, we declare that what We claim is- 1. In a brush-holder for dynamo-electric machines or the like, the combination with a casing, of a brush movably mounted therein, a fluid-pressure device adapted to retain said brush in contact with the commutator, a fluid-supply pipe supporting the said casing, said casing being adapted to be adjusted thereon, substantially as described.

2. In a brush-holder for dynamoelectric machines or the like, the combination with a movable brush, of a fluid-pressure device adapted to retain said brush in contact with the commutator and means for preventing the back movement of saidv fluid-pressure de vice, substantially as described.

3. In a brush-holder for dynamo-electric machines or the like, the combination with a movable brush, of a pressure device adapted to retain said brush in contact with the commutator, and a secondary pressure device adapted to operate said brush when said former device is inoperative, substantially as described.

4. In a brush-holder for dynamoelectric machines or the like, the combination with a movable brush, of a fluid-pressure device adapted to retain said brush in contact with the commutator and a secondary pressure device adapted to operate said brush when said pneumatic-pressure device is inoperative, substantially as described.

5. In a brush-holder for dynamo-electric machines or the like, the combination with a movable brush, of a pressure device adapted to retain said brush in contact with the commutator, and. a secondary pressure device located between said former device and said brush and adapted to operate said brush when said former pressure device is inoperative, substantially as described.

6. In a brush-holder for dynamo-electric machines or the like, the combination with a movable brush, of a fluid-pressure device adapted to retain said brush in contact with the commutator, a coiled spring located between said pressure device and said brush, means for retaining said spring in compression after said pressure device has become inoperative whereby said spring will retain said brush in contact with the commutator when said fluidpressure device fails to operate, substantially as described.

7. In a brush-holder for dynamo-electric machines or the like, the combination with a movable brush, of a fluid-pressure device provided with a rod having at its ends a sliding foot, a cross-bar on said rod and a coiled spring around said rod between said crossbar and said foot, substantially as described.

8. In. a brush-holder for dynamo-electric machines or the like, the combination with a movable brush, of a fluid-pressure device pro vided with a rod having at its end a sliding foot-piece adapted to bear upon said brush, a cross-bar mounted on said rod, stationary racks, clips on said cross-bar adapted to en gage said racks, and a coiled spring around said rod between said cross-bar and sliding foot, substantially as described.

9. In a brush-holder .l'or dynamo-electric machines or the like, the combination with a movable brush, o'l aili1i(l'p1'essi1re device provided with a rod. having at its end a sliding foot-piece adapted to bear upon said brush, a cross-bar mounted on said rod, stationary racks, clips on said cross-bar adapted to en gage said racks, whereby said. cross-bar is locked against backward movement when said pneumatic device fails to operate, a coiled spring around said rod between. said cross-bar and said sliding foot, and a fluidpressure device adapted to bear against the side of said brush to prevent lateral movement of the same, substantially as described.

10. In a brush-holder For dynamo-electric machines and the like, the combination with a box or cylinder, of a piston sliding therein, a rod for transmitting the movement from said piston to the brush, means for applying pneumatic pressure to said piston, a bar or plate upon the rod, a spring arranged. be tween the bar or rod and the brush and m ochanism for locking the plate to retain the spring under compression notwithstanding 'that the air-pressure is removed from the piston, substantially as described.

11. In a brush-holder for dynamo-electric machines, and the like, wherein a brush is acted upon by air under pressure, the combi- ,nation with a guide in which the brush works, of a piston or presser acting laterally upon the brush for retaining the same in contact with the guide-walls, substantially as and for the purpose described.

CHARLES l/VILLIAM SPEIRS. JULIUS FRITH.

Witnesses to the signature of Charles VVilliam. Speirs:

C. G. REDFERN, A. ALBUT'r. Witnesses to the signature of Julius Frith:

JOHN HANDLE TI-IORNHILL. JAMES STEW'ART BROADFOO'I. 

